Charles r



Oct. 27, 1936. c. R. BARNETT FURNACE CONTROL Filed Dec. 27, 1933 3vSheets-Sheet 1 FigJ Fig.2

INVENTOR fiar/esRBame/t :ms pawn/wk ATTORNEY Oct. 27, 1936.

C. R; BARNETT FURNACE CONTROL Filed Dec. 27, 1953 3 Sheets-Sheet 2 AnnINVENTOR Charles R. Barneff 0a. 27, 1936. R ARNETT 2,058,945

FURNACE CONTROL Filed Dec. 27, 1953 5 Sheets-Sheet 3 l I MagneficSwift/1 30 k9 I Mafor )8 INVENTOR Char/es RBa/"neff. Fly. 5 BY ATTORNEYPatented Oct. 27, 1936 PATENT OFFICE 2,058,945 rumvacn comor.

' Charles R. Barnett, Vineyard Harem. Masa; Stephen G. Luce, Jr.,Tisbury, Masa, executor 'otsaid Charles R. Barnett, deceased ApplicationDecember 27, 1933, Serial No. 704,127 9 Claims. (01. 110-32) Myinvention relates to improvements in combustion apparatus such ascoal-burning furnaces. The principal object of the invention is toprovide an improved automatic operating and control system for suchcoal-burning furnaces or boilers, and more particularly as applied toexisting types of furnaces or boilers.

A further object is to provide light-actuated means by which the systemis controlled, to give simplicity and improved economy of fuel andelectric current.

Other objects will appear in the following description.

Referring to the drawings:

Fig. 1 is a diagrammatic view of my system applied to a coal-burningboiler ofknown type;

Fig. 1a. is a fragmentary view of the system shown in Fig. 1, one of theelements of the system being illustrated in detail.

, Fig. 2 .is a fragmentary section of the grate operating mechanism, ashpit, and light-sensitive control device;

Fig. 3 is a detail view of the shaker eccentric mechanism;

Fig. i is a vertical section of the friction drive coupling; and v Fig.5 is a diagrammatic view of an alternative form of the system shown inFig. l.

The numeral it denotes an automatic fuel feed coal-burning boiler ofknown type, having a fuel hopper H from which fuel descends by gravitythrough a funnel it to a pair of sloping grates it and it, when thelatter are shaken. The

levers 22 of the grates l3 and M. Forks t3,

fastened to the shaker levers 22 by any suitable means, such as setscrews 2t, engage grooved sleeves 2t rotatably mounted in the eccentrics2B.

The numeral 26, Fig. 2, denotes a typical unit of the grate it, the unitit having a downwardly extending lever 21! and a rocker pin or axis 28.'A bar 29 pivoted to all levers Z'i is articulated to the shaker lever22 at the front of the furnace it, this internal shaker mechanism beingold and well-known.

The numeral 30 denotes an electric 1110i 1r adapted to drive the shaftI9 through a worm a id gear speed-reducer 3|, or other suitable means,and a safety coupling 32. p

Referring to Fig. 4, the numeral 33 denotes [a driving cup fixed to thedriven shaft 34 01 the speed-reducer 3|.

A driven flange 35 is fastened to the shaft |9. A presser ring 38slidable in the. cup 33 is urged into the latter by springs 34a underadjusting nuts 36, gripping the driven flange 35 between a pair offriction rings 31 and Referring again to Fig. 1, the numeral 39 denotesa relay of well-known form, adapted to be controlled by thelight-sensitive device l8 through an amplifier i8a. A magnetic switch40, preferl0 8| by a bi-metallic thermal element 82 anchored 20 at 83.In its normal, or restrained position, switch 80 establishes'a circuitthrough conductor M to a' solenoid 85, thence to the positive terminalof the source of electrical energy 4| through conductor t'll. Thus acircuit is completed from the negative terminal of the power source 4through time clock it, conductor 46, relay 3t, conductor 42, magneticswitch it, and finally to positive terminal ti. When a circuit is thusestablished, solenoid 85 operates plunger 86, and link Bl, to closeswitch it against the action of spring 89 thereby making 'a circuit tomotor 30 through conductors it and M. A heating coil 90 underlying thethermal' element 82 will be seen to be connected in series relation withswitch 88 and the conductors t8 and 39 to motor 30.

The timing mechanism of the clock it may be of the well-knownelectrically operated type, such as are shown in U. S. patents toWarren, #1,262,575; #1,522,988; or #1,533,67'7. A supply circuit 35 isprovided to run the clock; and the clock is provided with the usualdevices for tuming on and oh the control'circuit to conductor it at anydesired times and intervals.

The operation of the device as shown in Fig. 1 is as follows: At apredetermined time in the morning, the clock 43 closes the circuit toconductor 46, the relay 39 being in closed position. The switch element88 of the magnetic switch W is thereby closed, thus starting the motor38 by the current from the main line 4|, and revolving the shaft I9.'The eccentrics 2|, through the sleeves 25, oscillate the forks 23 andthe levers 22, thereby reciprocating the bars 29 and rocking the grateunits 26. This causes the ashes to drop into the ash pit l5, fresh coaldescending from the hopper II. The shaking action normally continuesuntil'live coals dropinto the pit. When this occurs, the light-sensitivedevice '18 isenergized, causing it to open the relay :9,

and thereby break the control circuit 46. This causes the magneticswitch 40 to break the main circuit 4|, thus stopping the motor 30, andstopping the grate-shaking action.

To provide for the contingency that live coals might not appear within agiven time (as would When the fire has been shaken until live coalsappear in the pit, the circuit is then held open by the light-sensitivedevice l8 so long as the glow remains. As soon as the glow ceases, ordies down enough to permit the device |8 to stop functioning, the relay39 again closes. Therefore if the circuit at the time clock is stillclosed, the shaking will begin again, to continue until new live coalsoperate the device l8 to stop the shaking.

But if meantime the elapsed time is such that the time clock has nowreached its circuit-opening position, then the shaking action cannotbegin again until the clock reaches a new, predetermined time-point, atwhich time the clock is set for a renewed making of the circuit forgrateshaking purposes. Thus, this setting of the circuit making andbreaking devices in the clock 43 may be predetermined at whatever provesto be the suitable periods for use.

In case a grate should stick, tending to stall the motor 30, the flange35, (Fig. 4), slips between the friction rings 31 and "a, but the motor,of course, draws a heavier current than is normally required. If thestoppage or retarding efiect should be only momentary, the excesscurrent is not maintained long enough to actuate the the thermal releaseand as soon as the'retarding force subsides.the friction surfaces oncemore grip the flange 35 and the shaking of the grate is resumed. If thestoppage continues, the safety coupling continues to slip and the motor'continues to draw excessive current until the thermal protective devicein the magnetic switch 40 comprising the heating coil 90, thermalelement 82 and spring 8| heats up and opens the motor circuit, afterwhich the obstacle is removed manually and the thermal device reset inthe usual way. a

The drawings illustrate a boiler with two grates. Should it be desiredto operate only one grate, the fork 23 may be removed from its lever 22by loosening the screw 24.

While a particular kind of bofler and grate are illustrated, it shouldbe understood that the illustrations are purely typical and the devicecan be applied to any desired furnace or boiler having a suitable shakergrate or grates.

Referring to Fig. 5, in which an alternative embodiment of the inventionis disclosed, the time clock 43' will be understood to be identical inall respects with the clock 43 of Fig. 1, but is shown in greater detailto facilitate an under-.

standing of the operation of the system. Similarly, the magnetic switch40' is preferably identical with the switch 4|] of Fig. l, but like thetime clock 43' is illustrated in greater detail to more clearly disclosethe operation of the system. The light sensitive cell ll, ampiifler ll'aand relay 39' will likewise be understood to be identical with thecorresponding elements of Fig. 1. This to establish the circuit to thestoker operating motor at predetermined intervals, as is the case in thedisclosure of Fig. 1, but it is anticipated that under some conditionsof operation it may be desirable to intermittently make and break thecircuit to the stoker driving motor during periods when the time clockfunctions to constantly operate the latter.

To this end, a time limit switch 50 is interposed in the circuit betweenthe time clock 43' and the driving motor ll of the grates. As shown, thetime limit switch 50 comprises a motor 5| arranged to rotate a gear 52rigidly connected to a cam 53 which in turn is adapted to operate aswitch arm 54, connected in series with relay 39.

Spring 54 normally tends to open a circuit from the time clock 43'through conductor 55, thence to relay 3! and magnetic'switch 40' tomotor 30 thus preventing operation of the stoker. For a more completedescription of the switch 50 reference may be had'to pages 66 to 68 ofMachine Design, of June, 1930, published by the Johnson PublishingCompany, Penton Building, Cleveland, Ohio.

Now considering the cooperative functions of time clock 43' and timelimit switch Ell: The time clock is permanently connected to the sourceof electrical energy 4| by lead wires 45' to constantly operate theclock motor 60. The motor 6|l-rotate's a dial 6| provided with angularlyadjustable, on and oil riders, 62 and 62a respectively. It will beunderstood that these riders may be positioned on dial 6| at any desiredpoints corresponding with the particular hour or time when it is desiredto complete or interrupt a circuit to motor 5| of time limit switch III,and thus effect intermittent operation of the stoker motor Ill. Theriders 62 and E ic are arranged to contact a laterally protrudingknobllb of a switch arm 63 which is maintained in on" and 01! positionsby a spring actuated toggle 820. A mercury reservoir 64, rigidlyconnected to switch arm 63 is provided with electrodes as shown, tocomplete a circuit from power source 4| through conductors 65 and 66 tomotor 5| when switch arm 63 occupies the position shown in Fig. 5. Ann63 is rockedto the position of Fig. 5 by the on rider 62 and is adaptedto be moved in a clockwise direction to its oif" position by rider 82awhich cams the knob 62b downwardly as dial 6| rotates in a clockwisedirection.

As will be apparent, the circuit from conductor 56 leads through switch54 relay 39' and thence to .magnetic switch 40' through conductor Ill.Magnetic switch 40' is, as has been pointed out, identical with theswitch 40 of Fig. 1a. Briefly, the conductor 10 is connected to a switcharm 18, which is normally restrained from movement under the influenceof a spring I1, by a thermal element I6 one end of which is anchored tothe base of magnetic switch 40'. When thus restrained, switch 18establishes a circuit through conductor 12 to solenoid II and then backto the negative terminal of power source 4|. Thus solenoid 'll operatesto close switch 13 thereby completing a circuit through heating element1! to motor ll.

The time limit switch I! will operate to alternately make and break thecircuit to motor 30' during any period of time when switch arm 83 ofclock 43' is in its on" position. The duration of the operating and idleperiods of the stoker motor may be modified by replacing the cam 53 withothers otdiflering configuration. Cams of Total time cycle Circuitclosed I 5 minutes 3 seconds to 3 minutes. 15 minutes 9 seconds to 9minutes. 30 minutes 18 seconds to 18 minutes. 1 hour 36 seconds to 36minutes.

By utilizing the time clock 43 for the main turning on of the circuit inthe morning and turning ofi at night, the time limit switch 50 can bemade use of for the shorter intervals of turning the' current on andoil", such as might be suitable for ensuring the proper shaking of thegrate at such times as might be necessary.

- It will be noted that the. thermal overload de-' vices of magneticswitches 40 and 40' will be effective to break the circuit to the stokermotor in the event that the thermal elements 82 or 76 respectively arecaused to move to the dotted line positions shown as a conseguence ofoverheating of the respective coils 80, or 15.

What is claimed is as follows:

1. In a furnace control, the combination with the shaker mechanism of afurnace, and an electric motor and circuit for operating the shakermechanism, of an electric light-sensitive device located in proximity tothe ash pit whereby to be actuated by the light from live coals, acontrol switch and circuit connected with the light-sensitive device forbreaking the electric motor circuit, and a timing device controlling theelectric motor circuit to make and break said circuit at selectedintervals when the said control switch-is in circuit making position.

2. In a furnace control, the combination set forth in claim 1, having inaddition thereto an auxiliary timing device operating an auxiliaryswitch in said electric motor circuitto make and break said circuit atshorter time intervals than the make and break periods of the firstmentioned timing device.

3. In a furnace control, the combination with the shaker mechanism ofthe furnace, and an electric motor for operating the same, of atimeclock-controlled circuit for said motor including a time clockswitch in said circuit, an'electrlc light-sensitive device located inproximity to the ash pit whereby to be acuated by the light from thelive coals, a circuit for. said light-sensitive device including a relaymechanism; a switch opened by said relay and located in said time clockcircuit; and switch opening and closing devices carried by said timeclock and operating upon said time clock switch to open and close saidtime clock circuit and thereby stop and start said electric motor atpredetermined times when the said relay switch is closed.

4. In a furnace control, the combination set forth in claim 1, andwherein the electric motor is connected to the shaker mechanism by afriction coupling, and the said circuit for said electric motor containsa thermal protective device to open said motor circuit when obstacleslocated in the shaker mechanism'prevent said' friction coupling fromdriving. v

5. The combination with a coal burning furnace including a grate,electrical means to actu ate said grate, an ashpit below the grate, anda source of electrical energy, of control .means to initiate andterminate operation of the grate actuating means comprising a. timesensitive switch connected to said source of energy in series with thegrate actuator, a normally closed relay switch in series with said grateactuating means and time switch, and a light sensitive device focused inthe ashpit and connected in series with the source'of energy, the timeswitch, and the actuator.

6. The combination with a coal burning furnace including a grate and anelectrical actuator therefor, an ashpit below the grate and a source ofelectrical'energy, of control means to initiate and terminate operationof said grate comprising a time controlled switch connected in serieswith said source of energy and said actuator, a normally. closed relayswitch in series with the actu ator and time switch,- and a photoelectric cell focused in said ashpit and arranged to open said relayswitch as an incident to the falling of live coals from said grate tothe ashpit.

7. The combination with a coal burning furnace including a grate and anelectrical actuator therefor, an ashpit below the grate and a source ofelectrical energy, of control means to initiate and terminate operationof said grate comprising a time controlled switch and a time limitswitch arranged to jointly and individually control a flow of currentfrom said source of energy to said actuator, a normally closed relayswitch in series with the actuator and time switches, and a lightsensitive cell focussed in said ashpit and arranged to open said relayswitch as an incident to the falling of live coals from said grate tothe ashpit, to defeat operation of said' first named switches.

8.'The combination with a furnace including a grate, an electricalactuator for said grate, and a source of electrical energy; of a timeclock in fixed circuit relation with said source of energy, a time limitdevice, a switch arranged to be controlled by said clock to make andbreak a circuit from said source of energy to said time limit device, aswitch arranged to be operated by said device to make and break acircuit from said source of energy through said first mentioned switchto said actuator, to cycle the latter at prea source of electricalenergy; of a time clock in fixed circuit relation with said source ofenergy, a time limit device, a switch arranged to be controlled by saidclock to make and break a circuit from said source of energy to'saidtime limit device, a switch arranged to be operated by said device tomake and break a circuit. from said source of energy through said firstmentioned switch to said actuator to cycle the latter at predeterminedshort intervals while the circuit from the first mentioned switch tosaid device is in circuit making position, and a light sensitive cellefiective to break the circuit from said source of energy through saidfirst and last mentioned switches to said actuator, as an incident tothe falling of live coals from said grate.

' C ARLES R. BARNETT.

(IERTIFICA'JLE 0F CORRECTION.

Patent No. 2,058,945. October 2'7, 1936.

CHARLES R. BARNETT.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 9, for the hyphenated word "circuit-breaking" readcircuitmaking; andthat the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 5th day of January, A. D. 1937.

Henry V'an Arsdale (Seal) Acting Commissioner of Patents.

